DIY Turntable is completed- pics here

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Hi All,

Many of you have probably already known about this project from another thread, "Intro from newbie TT builder". This thread has info about the design, and follows the process along. A sketch of the design is also available there.

First of all, thanks to all of you who gave me your input, and a special thank you to Frank Schroder and Chris Brady for their help and encouragement.

These are 4 of 12 photos I took since I finished it. The rest show a little more detail and most, if not all, will be posted later.

A brief comment about the base and plinth... The large white base was used as a microscope stand. It weighs in at 353 lbs, and I need to do a little structural work under the house to get it more solid. The two pieces used for the plinth are Afrormosia wood, from Africa. I cut the lower piece into the shape of a half-ellipse to match the shape of the base, and to also serve as a reminder of the shape of an elliptical stylus. The upper piece is a full ellipse. They are held together with screws and wood spacers.

Well, enjoy the pics!

Warm regards,

An externally hosted image should be here but it was not working when we last tested it.

OK- Details!

Tonearm- front to back...The cartridge is my old Ortofon X1-MC, pretty worn out, but sounds good on this rig. The headshell plate is titanium. You can see that the left and right wires are separated in the arm. The holes are about 1MM dia., accomplished by making grooves down the side of the inner 3/8" dia. piece of Black Palm. The outer piece is African Blackwood.
The wires leave the arm through 2 holes in the pivot piece (Aluminum). They are so short because the first time I ran the wires, they binded in this area and I had to cut them. Azimuth is adjusted here, and a screw in the top locks the two pieces together.
A tungsten shaft is press fitted into the back end of the pivot tube, and the counterweight is also tungsten.
The effective length of the arm is 283.88 MM/ 11.176". The effective mass is 12.5G.
The piece holding the lower magnet is aluminum.
The other materials used for the arm base are stainless steel and brass. All pieces are dowel pinned together, so can be disassembled and reassembled.
VTF was measured over the playing range from .06" below to .06" above the record surface and the total variation was .1G. Azimuth was checked also, using a dial indicator across the headshell, and did not change.
The arm lift is oil damped, but does not move slow enough to let the arm freefall onto the record. Instead of using a cam below the vertical shaft, I used a set screw going into the horizontal shaft. The length can be adjusted, which controls the amount of lift.

Reflex Record clamp- solid brass, and weighs 6 lbs.

I tried several materials for the trust ball/plate, and ended up using a ceramic ball and a delrin plate with a very small piece of teflon pressed into the delrin. This keeps the divot size to a minimum.

I covered the platter details fully enough in the other thread. Its final weight is 29lbs. I filled the lead shot cavities with glycol after the lead went in to improve visual clarity and to add weight. I don't know if this was a mistake sonically, but the rest of my system and my bad room acoustics will not be revealing that!

Despite the cart I am using, it does sound extremely good.

All I have is a bunch of scribbled sketches. I have also been asked to make one of these arms for someone. I think that I need to be clear about something- I made a near perfect copy of a Shroder tonearm, which is patented. It is a relatively simple design that any machinist worth his salt could copy from a picture. There are a few details that are in another realm completely and I admire the heck out of Frank Shroder for developing them and giving me hints as to how to proceed. Out of respect for Mr. Shroder, I feel that I must decline any requests to make the arm or provide detailed drawings of the parts. If I ever sell this arm, it will only be after notifying him and getting his permission, and you can be sure that I will share the profit generously with him.

Now, I'm not intending this to be a flame, this is just how I feel about it.

I am very, i mean very impressed

I am struggling with building mine, just not enough time for everything. I will post pictures when i am done,in the meantime you just enjoy the results. Do you have another arm you can put on the table and compare? I also admire your integrity regarding the issues of the patents. You are obviously a better machinist than i will ever be, and thank you for proving the point that is not an impossible task to build a good copy of the Schroder reference arm. The patents are actually well warranted ;-)

The motor

The motor was purchased from Teres Audio- it is a DC motor made by Maxon. I'm quite sure it is brushless. On/off, and speed regulation is accomplished by a sensor reading a strobe pattern on the bottom of the platter. To start the platter, I just start it turning by hand. A red LED on the motor indicates "Coming up to speed, Captain!", and a green LED indicates that speed is being maintained.

One thing that this is useful for is that if I even have a problem with the bearing binding, etc., the green LED won't come on.

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